//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8761 SUBJECT: GRB 090102: TAROT Calern observatory optical observations DATE: 09/01/02 03:08:29 GMT FROM: Alain Klotz at CESR-CNRS Klotz, A. (CESR-OMP), Gendre, B. (LAM_OAMP), Boer M. (OHP), Atteia J.L. (LATT-OMP) report: We imaged the field of GRB 090102 detected by SWIFT (trigger 338895) with the TAROT robotic telescope (D=25cm) located at the Calern observatory, France. The observations started 40.8s after the GRB trigger (6.8s after the notice). The elevation of the field decreased from from 68 degrees above horizon and weather conditions were good. We detect a new fading source in the error box given by SWIFT at the following position (+/- 1 arcsec): RA(J2000.0) = 08h 32m 38.1s DEC(J2000.0) +33d 11' 45.3" OT was R~15.3 at about 100s after GRB. Magnitudes were estimated with the nearby USNO-B1 stars and are not corrected for galactic dust extinction. N.B. Galactic coordinates are lon=189.8804 lat=+34.6651 and the galactic extinction in R band is 0.1 magnitudes estimated from D. Schlegel et al. 1998ApJ...500..525S. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8762 SUBJECT: GRB 090102: Swift detection of a burst with an optical counterpart DATE: 09/01/02 03:08:41 GMT FROM: David Burrows at PSU/Swift V. Mangano (INAF-IASFPA), S. D. Barthelmy (GSFC), D. N. Burrows (PSU), N. Gehrels (NASA/GSFC), S. T. Holland (CRESST/USRA/GSFC), E. A. Hoversten (PSU), J. A. Kennea (PSU), V. La Parola (INAF-IASFPA), W.B Landsman (GSFC), C. B. Markwardt (CRESST/GSFC/UMD), F. E. Marshall (NASA/GSFC) and B. Sbarufatti (INAF-IASFPA) report on behalf of the Swift Team: At 02:55:45 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 090102 (trigger=338895). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 128.259, +33.092 which is RA(J2000) = 08h 33m 02s Dec(J2000) = +33d 05' 29" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a multi-peaked structure with a duration of about 30 sec starting about 15 sec before the trigger. The peak count rate was ~7000 counts/sec (15-350 keV), at ~2 sec after the trigger. The XRT began observing the field at 03:02:13.1 UT, 387.2 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 128.2423, +33.1142 which is equivalent to: RA(J2000) = 08h 32m 58.15s Dec(J2000) = +33d 06' 51.1" with an uncertainty of 6.1 arcseconds (radius, 90% containment). This location is 94 arcseconds from the BAT onboard position, within the BAT error circle. No event data are yet available to determine the column density using X-ray spectroscopy. UVOT took a finding chart exposure of nominal 150 seconds with the White filter starting 395 seconds after the BAT trigger. There is a candidate afterglow in the list of sources generated on-board at RA(J2000) = 08:32:58.54 = 128.24391 DEC(J2000) = +33:06:51.2 = 33.11421 with a 90%-confidence error radius of about 1.10 arc sec. This position is 4.8 arc sec. from the center of the XRT error circle. The estimated magnitude is 18.11. No correction has been made for the expected extinction corresponding to E(B-V) of 0.05. Burst Advocate for this burst is V. Mangano (vanessa AT ifc.inaf.it). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8763 SUBJECT: GRB 090102: REM observations of a bright afterglow DATE: 09/01/02 03:30:14 GMT FROM: Stefano Covino at Brera Astronomical Observatory S. Covino, P. D'Avanzo, L.A. Antonelli, D. Malesani, D. Fugazza, L. Calzoletti, S. Campana, G. Chincarini, M.L. Conciatore, S. Cutini, V. D'Elia, F. D'Alessio, F. Fiore, P. Goldoni, D. Guetta, C. Guidorzi, G.L. Israel, E. Maiorano, N. Masetti, A. Melandri, E.J.A. Meurs, L. Nicastro, E. Palazzi, E. Pian, S. Piranomonte, L. Stella, G. Stratta, G. Tagliaferri, G. Tosti, V. Testa, S.D. Vergani, F. Vitali report on behalf of the REM team: The robotic 60-cm REM telescope located at La Silla (Chile) observed automatically the field of the GRB 090102 (Mangano et al. GCN8762) starting about 35s after the burst (26s after the alert). We detect a bright object in our first R- and H-band images consistent with the optical counterpart identified by UVOT (Mangano et al. GCN8762) and TAROT (Klotz et al. GCN 8761). The object is approximately R~14.2 (relative to nearby USNO-B1 stars) and H~12 (relative to nearby 2MASS stars) at about 1min after the burst. Further observations are in progress //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8764 SUBJECT: GRB 090102: TAROT Calern observatory optical light curve DATE: 09/01/02 05:14:46 GMT FROM: Alain Klotz at CESR-CNRS Klotz, A. (CESR-OMP), Gendre, B. (OAMP), Boer M. (OHP), Atteia J.L. (LATT-OMP) report: We analyzed images of GRB 090102 detected by SWIFT (trigger 338895) with the TAROT at the Calern observatory, France. In our previous GCN Circ. (9761) we made a mistake in the celestial coordinates of the optical afterglow. TAROT position is compatible with UVOT (Mangano et al. GCNC 8762). The first image is trailed with a duration of 60.0s (see the description in Klotz et al., 2006, A&A 451, L39) and we detect the growth of the optical light curve that culminates at t0+60s (+/- 3s) with a brightness R=13.4 (i.e. ~40s after the end of the gamma activity). We calibrated magnitudes in R band using NOMAD1 1231-0209716 (R=13.31). After t0+60s, the decay of the afteglow is classic with a decay of alpha=1.6 +/- 0.2. Hereafter, TAROT Calern data (tstart and tend are expressed in seconds after the BAT trigger t0): tstart tend R dR 40.8 46.8 14.3 0.2 46.8 52.8 13.6 0.1 52.8 58.8 13.4 0.1 58.8 64.8 13.4 0.1 64.8 70.8 13.5 0.1 70.8 76.8 13.7 0.1 76.8 82.8 13.7 0.1 82.8 88.8 14.0 0.1 88.8 94.8 14.1 0.1 94.8 100.8 14.3 0.1 107.6 137.6 14.4 0.2 144.6 174.6 14.9 0.2 181.6 211.6 15.5 0.3 Further observations are in progress //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8765 SUBJECT: GRB 090102: Enhanced Swift-XRT position DATE: 09/01/02 07:31:44 GMT FROM: Phil Evans at U of Leicester A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester) report on behalf of the Swift-XRT team. Using 1798 s of XRT Photon Counting mode data and 4 UVOT images for GRB 090102, we find an astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 128.2442, +33.1145 which is equivalent to: RA (J2000): 08h 32m 58.60s Dec (J2000): +33d 06' 52.1" with an uncertainty of 1.7 arcsec (radius, 90% confidence). This position may be improved as more data are received. The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401 http://www.swift.ac.uk/xrt_positions/Goad.pdf), the current algorithm is an extension of this method. This circular was automatically generated, and is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8766 SUBJECT: GRB 090102: NOT redshift DATE: 09/01/02 09:29:37 GMT FROM: Pall Jakobsson at U Hertfordshire Antonio de Ugarte Postigo (ESO), Pall Jakobsson (U. Iceland), Daniele Malesani, Johan P. U. Fynbo (DARK/NBI), Elaine Simpson and Susana Barros (Queen's University Belfast) report: We observed the field of GRB 090102 (Mangano et al., GCN 8762) with the NOT/ALFOSC starting on Jan 2 at 03:33 (38 minutes after the burst onset). The optical afterglow detected by Klotz et al. (GCN 8761) and Mangano et al. is detected with R ~ 19.6 (based on unfiltered images) at the following coordinates (J2000, 0.5" error): RA: 08:32:58.54 Dec.: +33:06:51.1 A 45-min low-resolution spectrum was also obained (2 hours post burst). A firm upper limit of z < 2.1 can be placed on the redshift of GRB 090102 from the lack of Ly-alpha forest lines in the spectrum of the afterglow. The spectrum also displays several metal lines, including Fe II, Mg II, Mg I, Al II, Al III and C IV, at a redshift of z = 1.547. No other significant lines are visible. We therefore conclude that z = 1.547 is the redshift of GRB 090102. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8767 SUBJECT: GRB 090102: Swift XRT refined analysis DATE: 09/01/02 16:30:08 GMT FROM: Vanessa Mangano at INAF-IASFPA V. Mangano, V. La Parola, B. Sbarufatti (INAF-IASF PA) report of behalf the Swift XRT team: We have analysed 6 orbits of Swift XRT data of GRB 090102 (Mangano et al. GCN Circ. 8762), consisting of 241 s in WT mode and 6.7 ks in PC mode. The XRT observation started 393 s after the trigger. The XRT light curve is well fitted by a single power-law with slope -1.32 +/- 0.01, and if decaying at this rate the source will reach a count rate level of 0.02 counts/s after one day. The WT spectrum is well fitted by an absorbed power-law with photon index 1.7 +/- 0.1, Galactic NH = 4.0e20 cm^-2 (Kalberla et al. 2005) and intrinsic absorption column of (3.8 +/- 2.0) e21 cm^-2 at the measured redshift z = 1.547 (De Ugarte Postigo et al. GCN Circ. 8766). The average observed [unabsorbed] flux during the WT observation is 6.2e-10 [7.2e-10] erg cm^-2 s^-1. The PC spectrum, extracted from about T+630 s to T+25 ks, is also well fitted by an absorbed power law with photon index 1.8 +/- 0.1, Galactic NH = 4.0e20 cm^-2 and and intrinsic NH = (7.0 +/- 2.0) e21 cm^-2 at z = 1.547. The average observed [unabsorbed] flux during the PC observation is 2.8e-11 [3.5e-11] erg cm^-2 s^-1. The rate to flux conversion factor is 1.3e-10 erg cm^-2 counts^-1. This is an official product of the Swift XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8768 SUBJECT: GRB 090102: Swift burst of interest DATE: 09/01/02 16:34:41 GMT FROM: Vanessa Mangano at INAF-IASFPA V. Mangano (INAF-IASF PA), S. Bathelemy (GSFC), P. A. Curran (UCL-MSSL), N. Gehrels (NASA/GSFC), D. Burrows (PSU) report on behalf the Swift team: Based on its bright multiwavelength emission and good sun angle, the Swift team declares GRB 090102 to be a burst of interest to be followed by Swift to late time. We encourage ground based follow-ups and cooperation of the scientific community in revising Swift observation plans according to results. Please post your results / plans or send us informal information. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8769 SUBJECT: GRB 090102: Swift-BAT refined analysis DATE: 09/01/02 16:35:19 GMT FROM: Scott Barthelmy at NASA/GSFC T. Sakamoto (GSFC/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), V. Mangano (INAF-IASFPA), C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. N. Ukwatta (GWU) (i.e. the Swift-BAT team): Using the data set from T-239 to T+963 sec from recent telemetry downlinks, we report further analysis of BAT GRB 090102 (trigger #338895) (Mangano, et al., GCN Circ. 8762). The BAT ground-calculated position is RA, Dec = 128.248, 33.107 deg, which is RA(J2000) = 08h 32m 59.5s Dec(J2000) = +33d 06' 25.7" with an uncertainty of 1.4 arcmin, (radius, sys+stat, 90% containment). The partial coding was 6%. The mask-weighted light curve shows approximately 4 overlapping peaks starting at ~T-14 sec, peaking at ~T+2 sec, and ending at ~T+15 sec. T90 (15-350 keV) is 27.0 +- 2.2 sec (estimated error including systematics). The time-averaged spectrum from T-13.9 to T+18.7 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.36 +- 0.08. The fluence in the 15-150 keV band is 6.8 +- 0.3 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+1.68 sec in the 15-150 keV band is 5.5 +- 0.8 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/338895/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8770 SUBJECT: Swift UVOT observations of GRB 090102 DATE: 09/01/02 17:15:34 GMT FROM: Peter Curran at MSSL P.A. Curran (UCL-MSSL), V. Mangano (INAF-IASF PA) and S.T. Holland (GSFC) on behalf of the Swift/UVOT team. The Swift Ultra-Violet/Optical Telescope (UVOT) began settled observations of the Swift localised GRB 090102 (#338895; Mangano et al., GCN 8762) ~400 seconds after the BAT trigger. An afterglow, consistent with the enhanced XRT position (Beardmore et al., GCN 8765) and with the afterglow candidate of Klotz et al. (GCN 8761), is detected at the position reported by Mangano et al. (GCN 8762). The source is detected in the initial optical observations but quickly fades (with alpha ~ 0.9 +/- 0.2 in white filter) below detection limits. The initial magnitudes (or 3 sigma limits) are: Filter t_mid(s) Exp(s) Mag wh 470. 147. 18.04 +/- 0.04 v 382. 10. 17.02 +/- 0.29 b 660. 19. 18.35 +/- 0.27 u 635. 19. 17.89 +/- 0.26 uvw1 3547. 255. >19.99 uvm2 6278. 197. >19.67 uvw2 1035. 388. >20.45 The detection in u along with the limits in uvw1 and bluer is consistent with a redshift of approximately ~1.8 < z < ~2.5 and with the spectroscopic redshift suggested by de Ugarte Postigo et al. (GCN 8766). The values quoted above are in the UVOT photometric system (Poole et al. 2008, MNRAS, 383, 627). They are not corrected for the expected Galactic extinction corresponding to a reddening of E(B-V)=0.047 mag in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8771 SUBJECT: GRB 090102: GROND observations of the optical afterglow DATE: 09/01/02 23:59:05 GMT FROM: Paulo M. J. Afonso at MPE GRB 090102: GROND observations of the optical afterglow P. Afonso, T. Kruehler (both MPE Garching), S. Klose (TLS Tautenburg), and J. Greiner (MPE Garching) report on behalf of the GROND team: GROND (Greiner et al. 2008, PASP 120, 405), mounted at the 2.2m ESO/MPI telescope at La Silla Observatory (Chile),started observations of the field of GRB 090102 (Mangano et al. 2008, GCN #8762) in g'r'i'z'JHK at 05:25 UTC, 2.50 h after the burst. Preliminary photometry yields the following r' band magnitudes of the optical afterglow (Klotz et al., GCN #8761, and also GCNs #8762, #8763, #8764, #8766 and #8770), calibrated against SDSS field stars. T_mid[s] Exp[s] AB Mag MagErr ------------------------------- 9042 66 20.58 0.05 9158 66 20.59 0.04 9265 66 20.58 0.03 9373 66 20.59 0.06 9515 115 20.59 0.04 9711 115 20.65 0.02 9903 115 20.67 0.02 10091 115 20.66 0.03 10423 375 20.70 0.02 10868 375 20.78 0.02 11320 375 20.79 0.02 11780 375 20.86 0.02 The quoted error is statistical only. There is an additional systematic error in the absolute calibration using SDSS field stars which is expected to be in the 0.05 mag range. In this time interval, the light curve is well described with a single power law of index 1.0 +/- 0.1, compatible with the value reported by Curran et al. (GCN #8770). Comparing against the early TAROT data (Klotz et al., GCN #8764), this indicates a flattening of the light curve. If the afterglow continues to decline with this power law, we predict r' band magnitudes of ~23.1 at 1 day and ~24.3 at 3 days after the burst. After correcting for a Galactic foreground extinction corresponding to a reddening of E_(B-V)=0.05 (Schlegel et al. 1998), the g' to K band SED is well described with a power law of spectral index beta = 1.0 +- 0.2. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8772 SUBJECT: GRB 090102 Observations from IAC80 DATE: 09/01/03 01:31:48 GMT FROM: Antonio Deugarte at IAA-CSIC A. de Ugarte Postigo (ESO), L. Blanco (IAC) A.J. Castro-Tirado (IAA-CSIC), report on behalf of a larger collaboration: We have observed the field of GRB090102 (Mangano et al., GCN 8762) from the IAC80 telescope at Izaņa Observatory in Tenerife (Spain). A 6x300s combined exposure with mean epoch 2.92 Jan 2009 (19.2h after the burst) shows the afterglow (Klotz et al., GCN 8761) with R=22.6+/-0.3, as compared to stars of the UNSO-B1.0. This is consistent with the prediction of Afonso et al. (GCN 8771) for day 1. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8773 SUBJECT: GRB 090102: P60 Imaging and P200 Spectroscopy DATE: 09/01/03 01:55:08 GMT FROM: S. Bradley Cenko at Caltech S. B. Cenko (UC Berkeley), A. Rau and M. Salvato (Caltech) report on behalf of a larger collaboration: We have imaged the field of GRB090102 (Mangano et al., GCN 8762) with the automated Palomar 60-inch telescope beginning at 03:46 on 2 Jan 2008 UT (~ 50 min after the burst). Observations were taken in the R, i', and g' filters and continued throughout the night until sunrise roughly 10 hours later. The optical afterglow (Klotz et al., GCN 8761, Covino et al., GCN 8763) is well detected in all three filters. All three bands exhibit a relatively smooth power-law decay with index ~ 0.9, consistent with the value reported by Afonso et al. (GCN 8771). We report here the following subset of our R-band observations: Tmid (s) Texp (s) Mag Err -------------------------------------- 3190.2 120.0 19.75 0.13 5266.2 120.0 20.02 0.06 7704.3 120.0 20.41 0.07 9973.9 120.0 20.56 0.07 11911.5 120.0 20.78 0.08 14068.6 120.0 21.01 0.09 16144.7 120.0 21.09 0.09 18522.6 600.0 21.23 0.06 20631.5 600.0 21.42 0.06 22756.7 600.0 21.58 0.07 24832.6 600.0 21.86 0.08 27994.7 1200.0 21.72 0.05 32188.5 1200.0 22.02 0.06 36411.3 1200.0 21.93 0.11 Photometric calibration was performed relative to the SDSS DR7, with photometric transformations from Jordi, Grebel, & Ammons (A&A, 460, 2006). In addition, we have obtained a single 1800 s spectrum of the afterglow with the Double Beam Spectrograph mounted on the Palomar 200" Hale telescope at a mean epoch of Jan 2.22. The spectrograph was configured to provide wavelength coverage from the atmospheric cutoff to ~ 8000 A. We confirm the results of de Ugarte Postigo (GCN 8766), finding a single strong absorption system at z = 1.546. Given the lack of strong Ly-alpha absorption, we place a slightly stricter limit on the host redshift of z < 1.9. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8774 SUBJECT: GRB 090102: Hobby-Eberly Telescope Spectroscopy DATE: 09/01/03 07:13:58 GMT FROM: Antonino Cucchiara at PSU A. Cucchiara and D. B. Fox (Penn State) report: "Starting on 2009 January 2.24 UT we used the Marcario LRS spectrograph on the Hobby-Eberly Telescope (R ~ 230) to obtain a 1000s spectrum of the optical afterglow of GRB 090102 (Mangano et al., GCN 8762, Covino et al., GCN 8763). The spectrum covers the wavelength range 4200 to 10,000 Angstrom. Unfortunately the data were taken under bad seeing conditions and the average S/N is ~5. Based on a preliminary calibration we detect some absorption features which we identify as the MgII doublet (2796,2803) and MgI(2856) at redshift z = 1.55. This value is consistent with the redshift reported by de Ugarte Postigo et al. (GCN 8766) and Cenko et al. (GCN 8773). We thank the HET staff for performing this observation, in particular John Caldwell." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8776 SUBJECT: Konus-Wind observation of GRB 090102 DATE: 09/01/03 12:32:25 GMT FROM: Valentin Pal'shin at Ioffe Inst S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, P. Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf of the Konus-Wind team, report: The long GRB 090102 (Swift-BAT trigger #338895: Mangano et al., GCN 8762; Sakamoto et al., GCN 8769) triggered Konus-Wind at T0=10536.283 s UT (02:55:36.283). The burst light curve shows a multipeaked structure with a duration of ~30 s. As observed by Konus-Wind the burst had a fluence of 3.09(-0.25, +0.29)x10^-5 erg/cm2, and a 256-ms peak flux measured from T0+12.016 s of 5.10(-0.72, +0.74)x10^-6 erg/cm2/s (both in the 20 keV - 2 MeV energy range). The time-integrated spectrum of the burst (from T0 to T0+33.024 s) can be fitted (in the 20 keV - 2 MeV range) by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.86(-0.13, +0.14), and Ep = 451(-58, 73) keV (chi2 = 48.8/65 dof). Fitting by GRB (Band) model yields the same alpha and Ep, and only an upper limit on the high energy photon index: beta < -2.73 (chi2 = 68.8/64 dof). All the quoted errors are at the 90% confidence level. Assuming z = 1.547 (de Ugarte Postigo et al., GCN 8766) and a standard cosmology model with H_0 = 70 km/s/Mpc, Omega_M = 0.27, Omega_\Lambda = 0.73, the isotropic energy release E_iso ~1.9x10^53 erg, the peak luminosity (L_iso)_max ~ 7.8x10^52 erg/s, and Ep_rest ~1100keV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB090102_T10536/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8778 SUBJECT: GRB 090102: GRT Optical Observation DATE: 09/01/04 17:13:41 GMT FROM: Takanori Sakamoto at NASA/GSFC T. Sakamoto (UMBC/GSFC), D. Donato (ORAU/GSFC), N. Gehrels (GSFC), T. Okajima (JHU/GSFC), T. N. Ukwatta (GWU/GSFC), Y. Urata (Saitama U), C. Wallace (FGCU) We observed the field of GRB 090102 detected by Swift (trigger #338895; Mangano et al., GCN #8762) with the 14-inch Goddard Robotic Telescope (GRT) located at the Goddard Geophysical and Astronomical Observatory (http://cddisa.gsfc.nasa.gov/ggao/). Ten set of 5 sec and five set of 10 sec and 30 sec exposures were taken in the R filter starting from Jan. 2 03:11:58 (UT) about 16.2 min after the trigger. We do not detect the optical afterglow (Klotz et al., GCN #8761, Mangano et al., GCN #8762) both in the individual images and the combined image. The estimated three sigma upper limit of the combined image (total exposure of 250 sec) is ~17.9 mag using the USNO-B1 catalog. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8779 SUBJECT: VLA radio upper limit on GRB 090102 DATE: 09/01/04 19:25:06 GMT FROM: Poonam Chandra at U Virginia/NRAO Poonam Chandra (RMC) and Dale A. Frail (NRAO) report on behalf of the Caltech-NRAO-Carnegie GRB Collaboration: "We used the Very Large Array to observe the field of view toward GRB 090102 (GCN 8762) at a frequency of 8.46 GHz on 2009 Jan 03.35 UT. The GRB radio afterglow is undetected at 3-sigma level. The flux density at the Swift UVOT afterglow position (GCB 8762) is 91 +/- 49 uJy. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8780 SUBJECT: GRB 090102: optical decay DATE: 09/01/05 12:15:18 GMT FROM: Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst D. Malesani, J. P. U. Fynbo (DARK/NBI), A. de Ugarte Postigo (ESO), J. Gorosabel (IAA/CSIC), S. Barros, E. Simpson (QUB), report on behalf of a larger collaboration: We observed the afterglow of GRB 090102 (Mangano et al., GCN 8762; Klotz et al., GCN 8761) with the Nordic Optical Telescope equipped with ALFOSC, at several epochs. The decay in the R band is consistent with a single power law with slope alpha ~ 0.9 between 0.1 and 3 days after the GRB. This is in agreement with the early-time slopes reported by Afonso et al. (GCN 8771) and Cenko et al. (GCN 8773). There is marginal indication that the light curve may flatten at late times, which could be due to the presence of a host galaxy. Further observations are encouraged. A plot with the light curve, including data from GROND (GCN 8771), P60 (GCN 8773), and IAC80 (de Ugarte Postigo et al., GCN 8772) is posted at the following URL: http://www.astro.ku.dk/~malesani/GRB/090102/lc.png [GCN OPS NOTE(05jan09): Per author's request, the Klotz reference was changed from 8762 to 8761.] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8792 SUBJECT: GRB 090102: WSRT Radio Observations DATE: 09/01/09 16:39:06 GMT FROM: Alexander van der Horst at NASA/MSFC A.J. van der Horst (NASA/MSFC/ORAU), R.A.M.J. Wijers and A.P. Kamble (University of Amsterdam) report on behalf of a larger collaboration: "We observed the position of the GRB 090102 afterglow at 4.9 GHz with the Westerbork Synthesis Radio Telescope at January 8 18.88 UT to January 9 6.86 UT, i.e. 6.66 - 7.16 days after the burst (GCN 8762). We do not detect a radio source at the position of the optical counterpart (GCN 8766). The three-sigma rms noise in the map around that position is 72 microJy per beam. The formal flux measurement for a point source at the position of the optical counterpart is 12 +/- 24 microJy. We would like to thank the WSRT staff for scheduling and obtaining these observations." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8816 SUBJECT: GRB090102: MAGIC telescope GeV observation DATE: 09/01/16 12:16:42 GMT FROM: Markus Garczarczyk at MPI/MAGIC Gaug M. (IAC Tenerife), Antonelli L. A. (INAF Rome), Bastieri D. (Univ. Padova), Becerra J. G. (IAC Tenerife), Carosi A. (INAF Rome), Covino S. (INAF Rome), Galante N. (MPI Munich), Garczarczyk M. (IFAE Barcelona), La Barbera A. (INAF Palermo), Longo F. (INFN Trieste), Persic M. (Univ. Udine), Scapin V. (Univ. Udine), and Teshima M. (MPI Munich) for the MAGIC collaboration The MAGIC Imaging Atmospheric Cherenkov Telescope performed a follow-up observation of GRB090102 (Mangano et al., circular 8762). We started data taking with MAGIC at 03:14:52 UT under excellent observation conditions. The observation continued for 13149 s. No evidence for VHE gamma-ray emission above a (preliminary) analysis threshold of 89 GeV was found. A preliminary analysis, for the hypothesis of steady emission and assumption of a differential photon spectral index of -2.5, yields the following 95% CL differential flux upper limits, including a 30% systematic uncertainty on the telescope efficiency. (Because of the changing telescope sensitivities due to different zenith angle ranges during the observation of GRB090102, the data sample was split into 5 parts): E ( 80- 125 GeV): 2.30 * 10^-10 erg/cm^2/s E ( 125- 175 GeV): 1.61 * 10^-10 erg/cm^2/s E ( 175- 300 GeV): 0.34 * 10^-10 erg/cm^2/s E ( 300-1000 GeV): 0.04 * 10^-10 erg/cm^2/s for a time window from 03:14:01 UT to 04:21:01 UT E ( 80- 125 GeV): 1.12 * 10^-10 erg/cm^2/s E ( 125- 175 GeV): 0.50 * 10^-10 erg/cm^2/s E ( 175- 300 GeV): 0.20 * 10^-10 erg/cm^2/s E ( 300-1000 GeV): 0.07 * 10^-10 erg/cm^2/s for a time window from 04:21:01 UT to 05:31:00 UT E ( 125- 175 GeV): 1.02 * 10^-10 erg/cm^2/s E ( 175- 300 GeV): 0.30 * 10^-10 erg/cm^2/s E ( 300-1000 GeV): 0.20 * 10^-10 erg/cm^2/s for a time window from 05:39:00 UT to 06:02:00 UT E ( 125- 175 GeV): 2.40 * 10^-10 erg/cm^2/s E ( 175- 300 GeV): 0.49 * 10^-10 erg/cm^2/s E ( 300-1000 GeV): 0.25 * 10^-10 erg/cm^2/s for a time window from 06:02:00 UT to 06:25:00 UT E ( 175- 300 GeV): 0.40 * 10^-10 erg/cm^2/s E ( 300-1000 GeV): 0.11 * 10^-10 erg/cm^2/s for a time window from 06:25:00 UT to 07:02:00 UT We can also exclude emission of a constant flux in any 100s time bin smaller than: E ( 80- 125 GeV): 12.58 * 10^-10 erg/cm^2/s E ( 125- 175 GeV): 7.53 * 10^-10 erg/cm^2/s E ( 175- 300 GeV): 3.27 * 10^-10 erg/cm^2/s E ( 300-1000 GeV): 1.41 * 10^-10 erg/cm^2/s for a time window from 03:14:01 UT to 04:21:01 UT E ( 80- 125 GeV): 18.16 * 10^-10 erg/cm^2/s E ( 125- 175 GeV): 15.56 * 10^-10 erg/cm^2/s E ( 175- 300 GeV): 3.46 * 10^-10 erg/cm^2/s E ( 300-1000 GeV): 1.40 * 10^-10 erg/cm^2/s for a time window from 04:21:01 UT to 05:31:00 UT E ( 125- 175 GeV): 11.61 * 10^-10 erg/cm^2/s E ( 175- 300 GeV): 2.47 * 10^-10 erg/cm^2/s E ( 300-1000 GeV): 0.91 * 10^-10 erg/cm^2/s for a time window from 05:39:00 UT to 06:02:00 UT E ( 125- 175 GeV): 12.38 * 10^-10 erg/cm^2/s E ( 175- 300 GeV): 5.38 * 10^-10 erg/cm^2/s E ( 300-1000 GeV): 1.53 * 10^-10 erg/cm^2/s for a time window from 06:02:00 UT to 06:25:00 UT E ( 175- 300 GeV): 10.06 * 10^-10 erg/cm^2/s E ( 300-1000 GeV): 1.28 * 10^-10 erg/cm^2/s for a time window from 06:25:00 UT to 07:02:00 UT Further analysis, exploiting the recently upgraded event trigger, is still underway for energies below 80 GeV. This message can be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8856 SUBJECT: GRB 090102: HST observations and host galaxy DATE: 09/01/27 22:33:21 GMT FROM: Nial Tanvir at IofA U.Cambridge A.J. Levan (Warwick), D. Malesani (DARK/NBI), N.R. Tanvir (Leicester), A. Fruchter (STScI), J.P.U. Fynbo (DARK/NBI), J. Hjorth (DARK/NBI), A. de Ugarte Postigo (ESO), P. Curran (MSSL), J. Graham (STScI), K. Wiersema (U. Leicester) report: We observed the afterglow of GRB 090102 (Mangano et al. GCN 8762; Klotz et al. GCN 8761) using the Hubble Space Telescope and Wide Field Planetary Camera on the 26th Jan 2009. Observations were obtained over 3 orbits (6400s), using the F606W filter. At the location of GRB 090102 we find an obvious host galaxy underlying the GRB afterglow. The magnitude of the combined afterglow+ host at this time is R~24.5 (AB). Astrometry utilizing early images obtained at the NOT (de Ugarte Postigo et al GCN 8766) shows that the location of GRB 090102 is consistent with the centroid of the galaxy/afterglow combined light (offset = 0.09 +/- 0.06"). This suggests that the afterglow may still be contributing significantly at the current epoch. Estimates of the magnitude of any likely point source coincident with this are inevitably uncertain, but do allow for a continued decay with temporal index alpha~1. Later time observations are planned, and will allow an accurate subtraction of the host galaxy light. Images can be found at http://www.star.le.ac.uk/~anl/090102